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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. LOMI, 1974 Volume 40, Pages 142–147 (Mi znsl2691)

On a hierarchy of Brouwer constructive functionals

N. A. Shanin


Abstract: An account is given on a variant (obeying principles of the constructive mathematics) of hierarchy approach to make precise L. E. J. Brouwer's idea of the notion of arithmetical functional defined on unary number-theoretic functions and computable from a finite number of values of its argument. Given a constructive ordinal $\beta$ a formula is constructed expressing the relation $\ll t_0$ is a godelnumber of a general recursive function (representing a functional) which bars the node of universal spread with number $t_1$ on the height not exceeding $\beta\gg$. This formula is equivalent to one of the form $\exists t_2\forall t_3\exists t_4(\varphi(t_0,t_1,t_3,t_4)=0)$, $\varphi$ being Kalmar-elementary. Functionals satisfying this condition with $t_1=0$ are called constructive Brouwer functionals of rank $\beta$. Brouwer uniform continuity theorem for constructive Brouwer functionals of rank $\beta$ can be proved by induction on $\beta$.

UDC: 51.01:519.5+51.01:518.5



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